default be "throw error on conflict", as per discussions.  The GUC variable
is plpgsql.variable_conflict, with values "error", "use_variable",
"use_column".  The behavior can also be specified per-function by inserting
one of
	#variable_conflict error
	#variable_conflict use_variable
	#variable_conflict use_column
at the start of the function body.

The 8.5 release notes will need to mention using "use_variable" to retain
backward-compatible behavior, although we should encourage people to migrate
to the much less mistake-prone "error" setting.

Update the plpgsql documentation to match this and other recent changes.

but the transformed ArrayExpr claimed to have a return type of "domain",
even though the domain constraint was only checked by the enclosing
CoerceToDomain node. With this fix, the ArrayExpr is correctly labeled with
the base type of the domain. Per gripe by Tom Lane.

we need to check domain constraints. We used to do it correctly, but 8.4
introduced a separate code path for the "ARRAY[]::arraytype" case to infer
the type of an empty ARRAY construct from the cast target, and forgot to take
domains into account.

Per report from Florian G. Pflug.

User-defined consistent functions believes the check array
contains at least one true element which was not a true for
scanning pending list.

Per report from Yury Don <yura@vpcit.ru>

if the initial value of a string variable was NULL, which is entirely
possible.  Noted while experimenting with custom_variable_classes.

will work.  Per buildfarm results.

Per discussion, this should result in defaulting to SQL_ASCII encoding.
The original coding could not support that because it conflated selection
of SQL_ASCII encoding with not being able to determine the encoding.
Adjust pg_get_encoding_from_locale()'s API to distinguish these cases,
and fix callers appropriately.  Only initdb actually changes behavior,
since the other callers were perfectly content to consider these cases
equivalent.

Per bug #5178 from Boh Yap.  Not going to bother back-patching, since
no one has complained before and there's an easy workaround (namely,
specify the encoding you want).

directly.  This was a lot of trouble, but should be worth it in terms of
not having to keep the plpgsql lexer in step with core anymore.  In addition
the handling of keywords is significantly better-structured, allowing us to
de-reserve a number of words that plpgsql formerly treated as reserved.

for an arguably more pleasant display.

This is a preparatory patch for allowing a dynamic cursor name be used in the
ECPG grammar.

Author: Zoltan Boszormenyi

The main motivation for this is that it's required for Informix compatibility
in ECPG.

This patch makes the ECPG and core grammars a bit closer to one another for
these productions.

Author: Zoltan Boszormenyi

mainloop.c.  This ensures that postgres_fe.h is read before including
any system headers, which is necessary to avoid problems on some platforms
where we make nondefault selections of feature macros for stdio.h or
other headers.  We have had this policy for flex modules in the backend
for many years, but for some reason it was not applied to psql.
Per trouble report from Alexandra Roy and diagnosis by Albe Laurenz.

Apple has fixed that bug in 10.6.2, and we should encourage users to
update to that version rather than trusting this cosmetic patch.
As was recently noted by Stephen Tyler, this patch was only masking
the problem in the context of DROP TABLESPACE, but the failure could
occur in other places such as pg_xlog cleanup.

Add C comment about why there is no interval_abs():  it is unclear what
value to return:

    http://archives.postgresql.org/pgsql-general/2009-10/msg01031.php
    http://archives.postgresql.org/pgsql-general/2009-11/msg00041.php

In VACUUM FULL, an interrupt after the initial transaction has been recorded
as committed can cause postmaster to restart with the following error message:
PANIC: cannot abort transaction NNNN, it was already committed
This problem has been reported many times.

In lazy VACUUM, an interrupt after the table has been truncated by
lazy_truncate_heap causes other backends' relcache to still point to the
removed pages; this can cause future INSERT and UPDATE queries to error out
with the following error message:
could not read block XX of relation 1663/NNN/MMMM: read only 0 of 8192 bytes
The window to this race condition is extremely narrow, but it has been seen in
the wild involving a cancelled autovacuum process.

The solution for both problems is to inhibit interrupts in both operations
until after the respective transactions have been committed.  It's not a
complete solution, because the transaction could theoretically be aborted by
some other error, but at least fixes the most common causes of both problems.

Update wording of GET DIAGNOSTICS/FOUND, per David Fetter.

yytext.  This is a necessary change if we're going to have a lexer interface
layer that does lookahead, since yytext won't necessarily be in step with
what the grammar thinks is the current token.  yylval and yylloc should
be the only side-variables that we need to manage when doing lookahead.

Document that GET DIAGNOSTICS is affected by EXECUTE, while FOUND is
not.

of different parsers having different YYSTYPE unions that they want to use
with it.  I defined a new union core_YYSTYPE that is just the (very short)
list of semantic values returned by the core scanner.  I had originally
worried that this would require an extra interface layer, but actually we can
have parser.c's base_yylex (formerly filtered_base_yylex) take care of that at
no extra cost.  Names associated with the core scanner are now "core_yy_foo",
with "base_yy_foo" being used in the core Bison parser and the parser.c
interface layer.

This solves the last serious stumbling block to eliminating plpgsql's separate
lexer.  One restriction that will still be present is that plpgsql and the
core will have to agree on the token numbers assigned to tokens that can be
returned by the core lexer.  Since Bison doesn't seem willing to accept
external assignments of those numbers, we'll have to live with decreeing that
core and plpgsql grammars declare these tokens first and in the same order.

can be the name of a plpgsql cursor variable, which formerly was converted
to $N before the core parser saw it, but that's no longer the case.
Deal with plain name references to plpgsql variables, and add a regression
test case that exposes the failure.

like the core parser's code.  In particular, track locations at the character
rather than line level during parsing, allowing many more parse-time error
conditions to be reported with precise error pointers rather than just
"near line N".

Also, exploit the fact that we no longer need to substitute $N for variable
references by making extracted SQL queries and expressions be exact copies
of subranges of the function text, rather than having random whitespace
changes within them.  This makes it possible to directly map parse error
positions from the core parser onto positions in the function text, which
lets us report them without the previous kluge of showing the intermediate
internal-query form.  (Later it might be good to do that for core
parse-analysis errors too, but this patch is just touching plpgsql's
lexer/parser, not what happens at runtime.)

In passing, make plpgsql's lexer use palloc not malloc.

These changes make plpgsql's parse-time error reports noticeably nicer
(as illustrated by the regression test changes), and will also simplify
the planned removal of plpgsql's separate lexer by reducing the impedance
mismatch between what it does and what the core lexer does.

This was long ago superseded by the standard build process and main
SGML documentation.

* Pull the responsibility for %TYPE and %ROWTYPE out of the scanner,
letting read_datatype manage it instead.

* Avoid unnecessary scanner-driven lookups of plpgsql variables in
places where it's not needed, which is actually most of the time;
we do not need it in DECLARE sections nor in text that is a SQL
query or expression.

* Rationalize the set of token types returned by the scanner:
distinguishing T_SCALAR, T_RECORD, T_ROW seems to complicate the grammar
in more places than it simplifies it, so merge these into one
token type T_DATUM; but split T_ERROR into T_DBLWORD and T_TRIPWORD
for clarity and simplicity of later processing.

Some of this will need to be revisited again when we try to make
plpgsql use the core scanner, but this patch gets some of the bigger
stumbling blocks out of the way.

Keep track of language's trusted flag in InlineCodeBlock. Needed to support DO blocks for languages that have both trusted and untrusted variants.

into SQL expressions, to using the newly added parser callback hooks.

This allows us to do the substitutions in a more semantically-aware way:
a variable reference will only be recognized where it can validly go,
ie, a place where a column value or parameter would be legal, instead of
the former behavior that would replace any textual match including
table names and column aliases (leading to syntax errors later on).
A release-note-worthy fine point is that plpgsql variable names that match
fully-reserved words will now need to be quoted.

This commit preserves the former behavior that variable references take
precedence over any possible match to a column name.  The infrastructure
is in place to support the reverse precedence or throwing an error on
ambiguity, but those behaviors aren't accessible yet.

Most of the code changes here are associated with making the namespace
data structure persist so that it can be consulted at runtime, instead
of throwing it away at the end of initial function parsing.

The plpgsql scanner is still doing name lookups, but that behavior is
now irrelevant for SQL expressions.  A future commit will deal with
removing unnecessary lookups.

it works just as well to have them be ordinary identifiers, and this gets rid
of a number of ugly special cases.  Plus we aren't interfering with non-rule
usage of these names.

catversion bump because the names change internally in stored rules.

Pointed out by Debian's lintian.

behavior, and is so little used that no one has been interested in fixing it.
To ensure that possible uses are covered, remove the ALIAS declaration's
arbitrary restriction that only $n identifiers can be aliased.

(We could alternatively make RENAME act just like ALIAS, but per discussion
having two different ways to do the same thing is probably more confusing than
helpful.)

that are not handled by find_coercion_pathway, notably composite->RECORD.
Now that 8.4 supports composites as primary keys, it's worth dealing with
this case.

tarballs under 100 characters.  This should avoid failures with certain
untarring tools (WinZip and Midnight Commander have been mentioned as
likely suspects).  Per my proposal of yesterday.
catversion bumped since the initial contents of pg_proc change.

at the first keyword of the expression, rather than drawing a rather
artificial distinction between the ESCAPE subclause and the rest.
Per gripe from Gokulakannan Somasundaram and subsequent discusssion.

As proof of concept, modify plpgsql to use the hooks.  plpgsql is still
inserting $n symbols textually, but the "back end" of the parsing process now
goes through the ParamRef hook instead of using a fixed parameter-type array,
and then execution only fetches actually-referenced parameters, using a hook
added to ParamListInfo.

Although there's a lot left to be done in plpgsql, this already cures the
"if (TG_OP = 'INSERT' and NEW.foo ...)"  problem, as illustrated by the
changed regression test.

Windows doesn't do signal processing like other platforms do. It never
really worked, but recent changes to the signal handling made it crash.

This fixes bug #4961. Patch by Fujii Masao.

Itagaki Takahiro, with small changes by me and Simon.